background image

 BAND 

 

 HUMIDISTATS

TYPICAL

PNEUMATIC

/ A S S E M B L Y

Follow steps   through 4 of 

Unhook the coil spring of the element assembly from

the 

 assembly bracket (Fig. IO).

Unhook the bias spring from its anchor post.
Remove the frame post and mounting screw.
Lift the nozzle/flapper assembly from the base.
Remove the O-ring from the rear of the nozzle/flapper

assembly.
Disengage the other end of the bias spring from the
bracket hole. Do not lose the small pin located inside

the spring.
Assemble the O-ring and the bias spring to the

replacement nozzle/flapper assembly and reinstall in
reverse order.
Recalibrate the 

FILTER CARTRIDGE

Reinstall the tiumidistat cover.

 AND

M

O

U

N

T

I

N

G

SCREWS (4)

When replacing these parts, use extreme care to
prevent dirt, dust, or debris from entering various
openings of the Humidistat base or the restrictor
block.

Remove the 

 cover.

Remove the Humidistat.

Fig. Il. Restrictor Block Assembly and Filter

Cartidge Replacement.

Access to the restrictor block assembly and filter

cartridge is from the rear of the base assembly.

Remove the four mounting screws from the restrictor

block (Fig. 
Carefully lift off the restrictor block (Fig. 11).

Remove the flat rubber gasket from the restrictor

block. The filter cartridge is located in the gasket.

Remove the filter cartridge from the gasket.

Align the gasket on the base assembly, and insert the
new filter cartridge into the recess in the base with the

screen end of the filter exposed.

Place the new restrictor block over the hasket and

filter 

 and replace the four mounting screws.

Snap the 

 onto the mounting 

Recalibrate the 

 the 

 cover.

 9.5

Summary of Contents for HP970A

Page 1: ...tings to convert older models or competitors humidistats Figure 1 shows a typical HP970A 13 or HP972B two pipe hookup Figure 2 shows a typical HP972B one pipe hookup HP970A B HP972B MB VALVE SUPPLY N C C322 5 Fig 1 Typical HP970A 6 or HP972B Humidistat Two Pipe Hookup HP972B RESTRICTION BLUE HUMIDIFIER VALVE N C SUPPLY C3226 Fig 2 Typical HP972B Humidistat One Pipe Hookup SPECIFICATIONS Action HP9...

Page 2: ...outdoor temperature preventing condensation during extreme winter conditions The tools shown in Figure 3 and a sling psychrometer or Digital Relative Humidity Pen CCT915 are necessary to calibrate the Humidistats PEN CCT915 0 if the nylon sensing element becomes contaminated with oil grease or dust remove and clean it by meetly agitating it in an acetone solution Dry the element at room temperatur...

Page 3: ...oes not bleed off properly proceed with RECALIBRATION RECALIBRATION CAUTION These Humidistats are sensitive devices and should be handled with extreme care during calibration Do not breathe directly on the element when the cover is off Ensure the system is stabilized and the main air is maintained at normal pressure between 13 and 21 psi 90 and 145 kPa Factory calibration is 18 psi 125 kPa Remove ...

Page 4: ...HP97QA i AND HP9725 PNEUMATIC HUMIDISTATS Table 1 Common Problems Causes and Solutions 75 7195 ...

Page 5: ...HP970A BAND HP972B PNEUMATIC HUMIDISTATS RESSURE IS REDUCE 1 N O Z Z L E SEMBLY f CHECKTHE MAIN AIR PRESSURE AT THE PRV PRESSURE DROP IN THE LONG AIR Fig 5 Humidistat Troubleshooting Flowchart 75 7195 ...

Page 6: ...e flat on the hub of the setpoint cam and wheel assembly Check calibration of Humidistat and recalibrate if necessary Remove the Humidistat cover Remove the old Humidistat leaving the airhead connected to the mounting plate Discard the new mounting plate Align the port holes Fig 6 on the back of the replacement Humidistat with the air connections on the existing airhead Snap the new Humidistat ont...

Page 7: ...acement unit in reverse order Make certain that the two levers are free to move Recalibrate the Humidistat Reinstall the Humidistat cover CALIBRATION LEVER ARM7 RELIEF SPRING SPRING POST Fig 8 Back of the Humidistat Showing Relief Spring Connections SCREW __ CALIBRATION CALIBRATION LEVER HOOK r MOUNTING SCREW NO 4 x 3 16 PN HD NOZZLE FLAPPER ELEMENT CALIBRATIO ELEMENT L E V E L HOOK ASSEMBLY YOKE ...

Page 8: ...ng these parts use extreme care to prevent dirt dust or debris from entering various openings of the Humidistat base or the restrictor block Remove the humidistat cover Remove the Humidistat 3 6333 2 Fig Il Restrictor Block Assembly and Filter Cartidge Replacement Access to the restrictor block assembly and filter cartridge is from the rear of the base assembly Remove the four mounting screws from...

Page 9: ...t Covers Part Number Suffix Window insert Setpoint 20 80 RH o Window Insert 03040506070 Vhen ordermg use complete part number rncludrng three digrt suttrx 14004407 XXX Covers are paintable See HP970 72 and TP970 74 Pneumatic Sensors Humidistats and Thermostats Installation instructions 955597 for painting information ACCESSORIES Table 4 HP970A B and HP9728 Pneumatic Humidistat Accessories Parts Li...

Page 10: ...lping You Control Your World 75 7195 8 89 By using this Honeywell literature you agree that Honeywell will have no liability for any damages arising out of your use or modification to the literature You will defend and indemnify Honeywell its affiliates and subsidiaries from and against any liability cost or damages including attorneys fees arising out of or resulting from any modification to the ...

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